Biomedical subjects

Gerhard Schroth

Publications and source records attributed to Gerhard Schroth.

14 recordsLinked to original sources

PubMed2003

Pre- and in-hospital delays from stroke onset to intra-arterial thrombolysis.

BACKGROUND AND PURPOSE: Thrombolysis for treatment of acute ischemic stroke should be administered as fast as possible after symptom onset. The aim of this study was to examine, in our tertiary care center, the time intervals preceding intra-arterial thrombolysis in order to accelerate and optimize the management of acute strokes. METHODS: Between January 1, 2000, and April 30, 2002, 597 patients with acute stroke were admitted to our stroke center. One hundred forty-eight patients underwent diagnostic arteriography, and 100 (16.8%) received intra-arterial thrombolysis. For all patients, we prospectively recorded and analyzed the time of symptom onset, admission, CT and/or MRI scan, diagnostic arteriography, and, if performed, intra-arterial thrombolysis. RESULTS: The mean time to arrival in the emergency department was 99 minutes for patients who were admitted directly (Bern patients), 127 minutes for those who were referred from community hospitals without a CT scanner (non-Bern/-CT patients), and 210 minutes for patients from hospitals with imaging facilities (non-Bern/+CT patients). The mean delay from symptom onset to treatment was 234 minutes for Bern patients, 269 minutes for non-Bern/-CT patients, and 302 minutes for non-Bern/+CT patients. The patients from the last group needed longer to receive intra-arterial thrombolysis than did patients who were admitted directly (P=0.002) or who were transferred from a hospital without a CT scanner (P=0.03). CONCLUSIONS: This prospective study indicates that direct referral without prior imaging at community hospitals shortens the time until intra-arterial thrombolysis. In addition, our in-hospital delay preceding intra-arterial thrombolysis is longer than the delays reported for intravenous thrombolysis and indicates potential for improvement.

Aged↗

PubMed2003

Reduced hippocampal anisotropy related to anteriorization of alpha EEG in schizophrenia.

Dysfunctions of the hippocampus have been suggested to be related to schizophrenia, and reduced connectivity with other brain regions may be a key for the pathophysiology. The aim of this study was to investigate the effect of white matter anomalies in the hippocampus, as a sign of altered connectivity, on the brain electrical activity. We investigated seven first episode schizophrenic patients and seven age, gender and education-matched controls with diffusion tensor imaging and resting EEG. Fractional anisotropy was computed based on diffusion tensor imaging data for the right and left hippocampus for both groups. No group differences were found in hippocampal fractional anisotropy, EEG spectral power and topography. However a significant correlation was found between more anterior alpha activity and lower fractional anisotropy of both hippocampi in schizophrenics, but not in controls. More anterior alpha activity has been described in schizophrenia. We conclude that this feature might depict a group of schizophrenic patients with reduced hippocampal connectivity.

Adolescent↗

PubMed2003

Does excessive memory load attenuate activation in the prefrontal cortex? Load-dependent processing in single and dual tasks: functional magnetic resonance imaging study.

Functional magnetic resonance imaging was used to investigate the relationship between cortical activation and memory load in dual tasks. An n-back task at four levels of difficulty was used with auditory-verbal and visual-nonverbal material, performed separately as single tasks and simultaneously as dual tasks. With reference to single tasks, activation in the prefrontal cortex (PFC) commonly increases with incremental memory load, whereas for dual tasks it has been hypothesized previously that activity in the PFC decreases in the face of excessive processing demands, i.e., if the capacity of the working memory's central executive system is exceeded. However, our results show that during both single and dual tasks, prefrontal activation increases continuously as a function of memory load. An increase of prefrontal activation was observed in the dual tasks even though processing demands were excessive in the case of the most difficult condition, as indicated by behavioral accuracy measures. The hypothesis concerning the decrease in prefrontal activation could not be supported and was discussed in terms of motivation factors. Similar changes in load-dependent activation were observed in two other regions outside the PFC, namely in the precentral gyrus and the superior parietal lobule. The results suggest that excessive processing demands in dual tasks are not necessarily accompanied by a diminution in cortical activity.

Adult↗

PubMed2003

Near-fatal cerebellar swelling caused by acute multifocal cerebellar necrosis.

We report a case of acute near-fatal cerebellar swelling, which was accompanied by multifocal cerebellar necrosis. Acute, near-fatal cerebellar swelling is a rare problem thought to be of parainfectious aetiology. Initiation by multifocal cerebellar necrosis has not been reported so far with this disorder.

Acute Disease↗

PubMed2003

Virtopsy, a new imaging horizon in forensic pathology: virtual autopsy by postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI)--a feasibility study.

Using postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI), 40 forensic cases were examined and findings were verified by subsequent autopsy. Results were classified as follows: (I) cause of death, (II) relevant traumatological and pathological findings, (III) vital reactions, (IV) reconstruction of injuries, (V) visualization. In these 40 forensic cases, 47 partly combined causes of death were diagnosed at autopsy, 26 (55%) causes of death were found independently using only radiological image data. Radiology was superior to autopsy in revealing certain cases of cranial, skeletal, or tissue trauma. Some forensic vital reactions were diagnosed equally well or better using MSCT/MRI. Radiological imaging techniques are particularly beneficial for reconstruction and visualization of forensic cases, including the opportunity to use the data for expert witness reports, teaching, quality control, and telemedical consultation. These preliminary results, based on the concept of "virtopsy," are promising enough to introduce and evaluate these radiological techniques in forensic medicine.

Adolescent↗

PubMed2002

Perfusion MRI abnormalities in the absence of diffusion changes in a case of moyamoya-like syndrome in neurofibromatosis type 1.

We report on a 12-year-old boy with neurofibromatosis type 1 who suffered a transient ischemic attack. Angiography revealed occlusion of intracranial arteries, moyamoya vessels and leptomeningeal collaterals. The conventional T2-weighted and the diffusion-weighted MRI images demonstrated no pathology. Dynamic first-pass postgadolinium T2* perfusion-weighted MRI depicted altered hemodynamics in the vascular territory of the left middle cerebral artery, which defined this region as ischemic tissue at risk. The patient suffered a repeat transient ischemic attack 5 days later.

Cerebral Angiography↗

PubMed2002

Fast contrast-enhanced MR whole-brain venography.

Our aim was to assess the value of a new fast contrast-enhanced MR venography (CE-MRV) sequence in the investigation of normal and diseased cerebral veins. Conventional time-of-flight (TOF) MRV is time consuming, with imaging for a single sequence taking many minutes. MRI was performed with a clinical 1.5-T scanner; conventional TOF MRV followed by CE-MRV was performed using a modified 3D first-pass MR angiography sequence. Ten control subjects without cerebral pathology were studied as well as ten patients with cerebral venous thrombosis for a total of 20 studies with both sequences. CE-MRV was able to provide a set of complete MRV images in a significantly shorter time than conventional MRV sequencing could. The field of view also provided greater coverage of the vessels of the head and neck. CE-MRV also provided more extensive small vein detail and provided a better demonstration of intraluminal defects, despite a slightly lower resolution. Both methods were equally suited for the demonstration of venous thrombosis and demonstrated all cases equally well; however, CE-MRV provided more detailed information by showing partially obstructed sinuses and by showing better the presence of cortical collateral venous drainage.

Adolescent↗

PubMed2002

Non-traumatic neurological emergencies: emergency neuroradiological interventions.

This article summarizes recent developments in the growing field of interventional neuroradiology for the treatment of acute cerebrovascular disease. We describe the possibilities in endovascular therapy of acute cerebral aneurysms using electrolytically detachable coils combined with trispan neck bridging devices and stent implantation to occlude acute wide neck aneurysms. Techniques and results of local intra-arterial thrombolytic therapy in acute stroke and central retinal artery occlusion are described and we discuss the potential for rapid, large-burden thrombus removal in cases of internal carotid artery thrombosis by rheolytic thrombectomy, percutaneous transluminal angioplasty and stent implantation. Emergency endovascular therapy using the transvenous approach to treat severe intracranial or intraocular hypertension and multifocal haemorrhagic venous infarction due to cerebral sinus thrombosis or dural fistulas is also described. In cases of acute bleeding of head and neck lesions following trauma, tumours after radiotherapy, arteriovenous malformations, epistaxis or from iatrogenic origin, angiography plays a major role in localizing the source of bleeding and occluding the damaged vessel during the same session using the same endovascular approach.

Adolescent↗

PubMed2002

Thrombolysis in patients with acute stroke caused by cervical artery dissection: analysis of 9 patients and review of the literature.

BACKGROUND: Results of recently published studies suggest that intravenous thrombolysis (IVT) and local intra-arterial thrombolysis (LIT) are feasible procedures in acute stroke after cervical artery dissection (CAD). OBJECTIVES: To describe 9 patients with acute stroke caused by CAD who were treated by LIT (n = 7) or IVT (n = 2) and to review the literature. METHODS: Retrospective analysis of clinical and neuroradiological findings; literature review from 1980 to present. MAIN OUTCOME MEASURE: Modified Rankin Scale (mRS) score. RESULTS: Of 7 patients treated with LIT, 3 had good outcomes (mRS score of 0-2) and 4 had bad outcomes (mRS score of 3-6) at 3 months. The 2 patients who had received IVT recovered to mRS scores of 0 and 3. Twenty-one patients were identified in the literature. Overall (N = 30), in the IVT group (n = 19), the outcome was good in 8 patients (42%) and bad in 11 (58%); in the LIT group (n = 11), 6 patients (55%) had a good outcome and 5 (45%) had a bad outcome. Overall, 47% (14/30) of the patients (IVT and LIT groups) had a good outcome. Total mortality was 13% (4/30). There were no secondary complications due to extension of wall hematoma or angiography. One symptomatic hemorrhage occurred. CONCLUSIONS: Thrombolysis is feasible in acute stroke caused by CAD. Local complications from extension of wall hematoma did not occur. Further prospective studies are needed to determine the safety and efficacy of thrombolysis in the special circumstance of acute stroke caused by CAD.

Acute Disease↗

PubMed2002

Duplex sonographic criteria for measuring carotid stenoses.

PURPOSE: The aim of this retrospective study was to determine optimal duplex sonographic criteria for use in our institution for diagnosing severe carotid stenoses and to correlate those findings with angiographic measurements obtained by the European Carotid Surgery Trial (ECST), North American Symptomatic Carotid Endarterectomy Trial (NASCET), and Common Carotid (CC) methods of grading carotid stenoses. METHODS: We analyzed the angiographic data using the ECST, NASCET, and CC methods and compared the results with the duplex sonographic findings. We then calculated the sensitivity, specificity, positive and negative predictive values, and accuracy of the duplex sonographic method. Taking these parameters into account, the optimal intrastenotic peak systolic velocity (PSV) and end diastolic velocity (EDV) were derived for diagnosing severe stenoses according to the 3 angiographic methods. RESULTS: Optimal PSV and EDV values for diagnosing a 70% or greater stenosis in our laboratory were as follows: with the NASCET method of angiographic grading of stenoses, PSV 220 cm/second or greater and EDV 80 cm/second or greater, and with the ECST and CC methods, PSV 190 cm/second or greater, and EDV 65 cm/second or greater. The optimal PSV and EDV for diagnosing a stenosis of 80% or greater with the ECST grading method were 215 cm/second or greater and 90 cm/second or greater, respectively. CONCLUSIONS: Duplex sonography is a sensitive and accurate tool for evaluating severe carotid stenoses. Optimal PSVs and EDVs vary according to the angiographic method used to grade the stenosis. They are similar for stenoses 70% or greater with the NASCET method and for stenoses 80% or greater with the ECST method.

Aged↗

PubMed2002

Acute disseminated encephalomyelitis in adults: a reappraisal of clinical, CSF, EEG, and MRI findings.

OBJECTIVES: To establish an adequate definition of acute disseminated encephalomyelitis (ADEM) in adults, based on our clinical observations of a case-series. METHODS: Over a period of three years 10 adult patients with a para- or postinfectious disseminated (diffuse or multifocal) syndrome of the CNS fulfilling predefined strict criteria for the diagnosis of ADEM were encountered and systematically followed. RESULTS: The age ranged from 21 to 62 years, two were men. MRI was normal in 5 patients and only mildly abnormal in the remaining patients. CSF was normal in 5 patients and mildly abnormal in the remainder, EEG was abnormal in 7/8 patients. All patients survived and were followed over a period of 30 months (range: 8 to 48 months). Nine patients were left with some residual defects, consisting most often of a mild cognitive impairment. CONCLUSIONS: The EEG as an investigation of brain function can be crucial in establishing the organic nature of disease. MRI is important to exclude other diffuse or multifocal encephalopathies. However, in contrast to previous reports in the literature abnormal MRI should not be considered mandatory in adult ADEM. Difficulties in the diagnosis of ADEM are discussed and the importance of clinical and paraclinical findings for establishing the diagnosis is outlined.

Adult↗

PubMed2002

Intra-arterial thrombolysis in 100 patients with acute stroke due to middle cerebral artery occlusion.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the safety and efficacy of local intra-arterial thrombolysis (LIT) using urokinase in patients with acute stroke due to middle cerebral artery (MCA) occlusion. METHODS: We analyzed clinical and radiological findings and functional outcome 3 months after LIT with urokinase of 100 consecutive patients. To measure outcome, the modified Rankin scale (mRs) score was used. RESULTS: Angiography showed occlusion of the M1 segment of the MCA in 57 patients, of the M2 segment in 21, and of the M3 or M4 segment in 22. The median National Institutes of Health Stroke Scale (NIHSS) score at admission was 14, and, on average, 236 minutes elapsed from symptom onset to LIT. Forty-seven patients (47%) had an excellent outcome (mRs score 0 to 1), 21 (21%) a good outcome (mRs score 2), and 22 (22%) a poor outcome (mRs score 3 to 5). Ten patients (10%) died. Excellent or good outcome (mRs score < or =2) was seen in 59% of patients with M1 or M2 and 95% of those with M(3) or M(4) MCA occlusions. Recanalization as seen on angiography was complete (thrombolysis in myocardial infarction [TIMI] grade 3) in 20% of patients and partial (TIMI grade 2) in 56% of patients. Age <60 years (P<0.05), low NIHSS score at admission (P<0.00001), and vessel recanalization (P=0.0004) were independently associated with excellent or good outcome and diabetes with poor outcome (P=0.002). Symptomatic cerebral hemorrhage occurred in 7 patients (7%). CONCLUSIONS: LIT with urokinase that is administered by a single organized stroke team is safe and can be as efficacious as thrombolysis has been in large multicenter clinical trials.

Adult↗

PubMed2002

Use of diffusion-weighted magnetic resonance imaging in differentiating purulent brain processes from cystic brain tumors.

OBJECT: Brain abscesses and other purulent brain processes represent potentially life-threatening conditions for which immediate correct diagnosis is necessary to administer treatment. Distinguishing between cystic brain tumors and abscesses is often difficult using conventional imaging methods. The authors' goal was to study the ability of diffusion-weighted (DW) magnetic resonance (MR) imaging to differentiate between these two pathologies in patients within the clinical setting. METHODS: Diffusion-weighted MR imaging studies and calculation of the apparent diffusion coefficient (ADC) values were completed in a consecutive series of 16 patients harboring surgically verified purulent brain processes. This study group included 11 patients with brain abscess (one patient had an additional subdural hematoma and another also had ventriculitis), two with subdural empyema, two with septic embolic disease, and one patient with ventriculitis. Data from these patients were compared with similar data obtained in 16 patients matched for age and sex, who harbored surgically verified neoplastic cystic brain tumors. In patients with brain abscess, subdural empyema, septic emboli, and ventriculitis, these lesions appeared hyperintense on DW MR images, whereas in patients with tumor, the lesion was visualized as a hypointense area. The ADC values calculated in patients with brain infections (mean 0.68 x 10(3) mm2/sec) were significantly lower than those measured in patients with neoplastic lesions (mean 1.63 x 10(3) mm2/sec; p < 0.05). CONCLUSIONS: Diffusion-weighted MR imaging can be used to identify infectious brain lesions and can help to differentiate between brain abscess and cystic brain tumor, thus making it a strong additional imaging modality in the early diagnosis of central nervous system purulent brain processes.

Adult↗

PubMed2002

Contrast-enhanced 3D MR angiography of the carotid artery: comparison with conventional digital subtraction angiography.

BACKGROUND AND PURPOSE: Since 1996, several preliminary studies have shown the usefulness of contrast material-enhanced MR angiography for imaging supraaortic vessels. The aim of this study was to compare the accuracy of contrast-enhanced 3D MR angiography with that of digital subtraction angiography (DSA) in the evaluation of carotid artery stenosis. METHODS: A blinded comparison of first-pass contrast-enhanced MR angiography with conventional DSA was performed in 120 patients (240 arteries). MR angiography was performed with a 1.5-T magnet with gradient overdrive equipment, by using a coronal radiofrequency-spoiled 3D fast low-angle-shot sequence after the intravenous injection of gadodiamide. The guidelines of the North American Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection (MIP) images and conventional catheter angiograms. RESULTS: Grading of stenoses on MR angiograms agreed with grading of stenoses on DSA images in 89% of arteries. In the severe stenosis group (70-99%), agreement was 93%. All internal carotid occlusions (n = 28) and seven of nine pseudo-occlusions were accurately detected with contrast-enhanced MR angiography. The correlation between MR angiography and DSA for determination of minimal, moderate, and severe stenoses and occlusion was statistically significant (r = 0.91, P<.001). CONCLUSIONS: This investigation with a large number of patients confirms that contrast-enhanced MR angiography could become a diagnostic alternative to DSA in the treatment of patients with carotid artery disease.

Adolescent↗